We study depth-$5$ algebraic circuits over small finite fields with restricted fan-in of the top product gates. We show that there exists an explicit degree-$d$ polynomial $P(\mathbf{x})$ such that any $\Sigma \Pi^{[\mathrm{poly(d)}]} \Sigma \Pi \Sigma$ circuit, computing $P(\mathbf{x})$, over a small finite field, requires size $2^{\Omega(\sqrt{d})}$. Our work builds upon ... more >>>

We investigate the closure properties of read-once oblivious Algebraic Branching Programs (roABPs) under various natural algebraic operations and prove the following.
- Non-closure under factoring: There is a sequence of explicit polynomials $(f_n(x_1,\ldots, x_n))_n$ that have poly(n)-sized roABPs such that some irreducible factor of $f_n$ does not have roABPs ... more >>>